The Marlins (with Heath Bell and John Buck) still seem to make the most sense to me, given each team's needs, but no such deal materialized.
I recall hearing buzz last winter suggesting the Red Sox and Mets had talked about swapping Bay and Josh Beckett, who was eventually traded to the Dodgers this summer. So, I wonder if a similar deal could be built around Bay and John Lackey, (12-12, 6.41 ERA) who will earn $30.5 million over the next two years. In that scenario, though, given Sandy Alderson's needs, he'd probably be better off with Bay.
Lastly, Mariners outfielders Chone Figgins and Franklin Gutierrez will combine to earn $15.5 million next year. Also, as Rubin points out, Bay is from Seattle. I'm not sure I'd want to take on two sub-par outfielders, while trading just one, but it's certainly a financial match...
At any rate, the larger point is that there are equally (if not worse) contracts around the game, which could pose possibilities for Alderson should he look to trade Bay this winter or spring.